Next.js color-mode

A helper for creating non-flickering and accessible themed applications

Features

🙉 Non-flickering
♿ Accessible (supports prefers-color-scheme)
🐱 Dynamic theme values
🐄 No additional dependencies
🧠 Agnostic to the way you style your app

Installation

$ npm i --save nextjs-color-mode

# or

$ yarn add nextjs-color-mode

Setup

First, you need to import ColorModeScript from nextjs-color-mode and place it somewhere in the _app.js file.

If you're using styled-components or emotion, you can put the contents of criticalThemeCss to GlobalStyles. Just make sure it's critical css, and at the top of your global styles.

// _app.js

import Head from 'next/head'
import { ColorModeScript } from 'nextjs-color-mode'

const criticalThemeCss = `
.next-light-theme {
--background: #fff;
--text: #000;
}

.next-dark-theme {
--background: #000;
--text: #fff;
}

body {
  background: var(--background);
  color: var(--text);
}
`

function MyApp({ Component, pageProps }) {
  return (
    <>
      <Head>
        <style dangerouslySetInnerHTML={{ __html: criticalThemeCss }} />
      </Head>
      <ColorModeScript />
      <Component {...pageProps} />
    </>
  )
}

Theme switcher (`useColorSwitcher`)

To implement theme switcher, you should use the useColorSwitcher hook

Note that every component that explicitly uses this hook should be rendered only on the client-side. Check out how we do this in the example

import { ColorModeStyles, useColorModeValue, useColorSwitcher } from 'nextjs-color-mode'

export default function ColorSwitcher(props) {
  const { toggleTheme, colorMode } = useColorSwitcher()

  return (
    <button onClick={toggleTheme}>
      Change theme to {colorMode === 'light' ? 'dark' : 'light'}
    </button>
  )
}

function useColorSwitcher(): {
    colorMode: string;
    changeTheme: (colorMode: 'light' | 'dark') => void;
    toggleTheme: () => void;
};

Using dynamic variables (`useColorModeValue`)

Sometimes you may want to omit the design system or need to hotfix something fast. Here's the solution for that.

export default function SomeComponent() {
  const [boxBgColor, boxBgCss] = useColorModeValue('box-color', 'blue', 'red')
  const [boxBorderColor, boxBorderCss] = useColorModeValue('box-border-color', 'red', 'blue')
  // the first item of the array returns CSS variable name
  // and the second one returns a special object that then gets parsed into a themable CSS variable

  return (
    <>
      <ColorModeStyles styles={[boxBgCss, boxBorderCss]} />
      <div style={{ width: '24rem', height: '12rem', backgroundColor: boxBgColor, border: "10px solid", borderColor: boxBorderColor }} />
    </>
  )
}

function useColorModeValue(name: string, lightThemeValue: string, darkThemeValue: string);

Do not use the same name twice, it may cause variable overriding and is hard to debug. Also using things like unique id, UUID or any randomly generated set of characters is a bad idea - it will display mismatch content warning and make it even harder to debug!

Support

If you're looking for help or simply want to share your thoughts about the project, we encourage you to join our Discord community. Here's the link: https://blazity.com/discord. It's a space where we exchange ideas and help one another. Everyone's input is appreciated, and we look forward to welcoming you.

Blazity/nextjs-color-mode